The present invention relates integrated circuits and, more particularly, to a comparator and clock signal generation circuit.
Crystal oscillator circuits are commonly used to generate oscillating signals and can be used to provide clock signals. Start-up of a crystal oscillator is achieved by applying a random noise signal that stimulates the crystal to begin to oscillate at its natural frequency. The signal generated by the crystal is then amplified and used to stimulate the crystal, gradually increasing the strength of the signal at the resonant frequency of the crystal until this frequency dominates the output of the crystal circuit.
However, during start-up of the crystal oscillator, some spurious frequencies may persist for significant periods of time, and can result in a poor or unstable clock signal being generated. Such an unstable clock signal may cause other circuits that rely on the clock signal to operate incorrectly.
It would be advantageous to have a circuit that reduces or limits the possibility of generating unstable clock signals.